Phenology and production of Hassaoui grapevines as affected by climate anomalies in Al Ahsa region.

Climate change is a dramatic crisis that has left severe impacts on viticulture. Phenological events over 41 years and annual climatic anomalies' data over these years in Al Ahsa region were procured. Annual temperature and wind speed anomalies had the strongest influence on all phenological events of the varieties White and Red Hassaoui, starting from the beginning of budburst until harvest. Moreover, the average yield of both varieties decreased significantly by 319.4 and 317 kg ha respectively between 1997 and 2019 in comparison with the interval of years 1979-1996. Earlier phenological events were positively correlated with annual temperature anomaly and negatively correlated with annual wind speed anomaly. The latter shortened the dates of occurrence of beginning and full veraison. Yield decreased with higher annual temperature, wind speed and total cloud cover anomalies, and lower annual total precipitation anomaly. Higher annual temperature and wind speed anomalies were correlated with a shorter period between beginning of budburst to beginning of veraison (P3). Shorter periods between beginning and full veraison (P6) and beginning of veraison and harvest (P7) of Red Hassaoui were positively correlated with annual precipitable water anomaly. Results suggest a high level of adaptation of both tested varieties to changing climate conditions in Al Ahsa, though irrigating vines after harvest on a weekly basis would help overcoming the minimal reduction in yield which was caused by the shortage in precipitation.